Experimental observations of the thermal stability of high-k gate dielectric materials on silicon

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

“…6 by the fact that the peak intensity of both films increases up to the same height and FWHM on annealing. A similar observation has been made by Lysaght et al, 33 in which 4 nm as-deposited ALD HfO 2 films grown on chemical oxide underlayers appear amorphous. Results in the same study 33 show that the percentage of the crystallinity achieved after annealing is independent of the as-deposited crystallinity.…”

Incipient amorphous-to-crystalline transition in HfO2 as a function of thickness scaling and anneal temperature

“…Correspondingly, interface performance enhancements of high-k/Si(1 0 0) systems have been realized [3], along with recent efforts to increase the permittivity of high-k materials through controlled incorporation of lanthanide series elements [4,5]. Central to all advanced dielectric film optimization endeavors has been the desire to circumvent crystallization of HfO 2 by alloying with Si and N to minimize adverse effects associated with precipitated impurity concentrations that may exacerbate leakage current pathways associated with grain boundary formation [6]. Concurrently, high resolution spectroscopic techniques capable of characterizing subtle film and interface stoichiometric variations as a function of gate stack layer deposition and subsequent anneal processing have emerged as critical requirements for the identification of microstructure driven mechanisms that limit the electrical performance of Hf-based complimentary metal oxide semiconductor (CMOS) devices [7].…”

Characterization of hafnium oxide grown on silicon by atomic layer deposition: Interface structure

“…deposited on silicon have shown presence of a silicon oxide interfacial layer [2]. Among these potential candidates, HfO 2 and its silicates and aluminates have been intensely studied because they exhibit good electrical properties and are thermally stable [3,4]. In previous studies, HfO 2 deposition has been carried out using metal organic chemical vapor deposition, jet vapor deposition, reactive sputtering, atomic layer deposition (ALD), and plasma enhanced ALD [2,[5][6][7][8].…”

“…In this work, HfO 2 films deposited by ALD of tetrakis(diethylamino)hafnium (Hf(DEA) 4 ) and moisture are characterized using angle resolved X-ray photoelectron spectroscopy (ARXPS), scanning transmission electron micrscopy (STEM), and electron energy loss spectroscopy (EELS). The results indicate that the HfO 2 /Si interface of the as-deposited ALD films are mostly free of silicate structure.…”